HM9270DHM 9270C/D DTMF RECEIVER General Description The HM 9270C/D is a complete DTMF receiver integrating both the bandsplit filter and digital decoder functions. The filter section uses switched capacitor techniques for high- and low-group filters and dial-tone rejection. Digital counting techniques are employed in the decoder to detect and decode all 16 DTMF tonepairs into a 4-bit code. External component count is minimized by on-chip provision of a differential input amplifier, clock-oscillator and latched 3-state bus interface. Features Complete receiver in an 18-pin package. Excellent performance. CMOS, single 5 volt operation. Minimum board area. Central office quality. Low power consumption. Power-Down mode (HM9270D only). Inhibit-mode (HM9270D only). Pin Configurations HM9270……